This invention relates to powered gate openers and more particularly to regulating the power used to open and close powered gates.
Powered gates are frequently employed to move gates, such as those which control access to a parking lot, to a gated community, or to private land, for example, by means of a power-drive unit which moves the gate between open and closed positions. The gate may move horizontally along a guide way or may swing about a vertical hinge axis to open and close the gate.
A typical power-drive unit for these gates includes an electric motor mechanically coupled to a gate to cause the gate to move between open and closed positions. The limits of movement of the gate itself are often set by use of conventional limit switches or by simply timing the cycle of opening or closing by approximation. Alternatively, the mechanism of the gate operator may be configured such that an approximate opened and closed position for the gate is set by the mechanical operation constraints of the mechanism itself.
The action of a gate through a cycle may also be controlled by use of a microprocessor executing a program and controlling the power unit. The term microprocessor is used herein and will be understood by those skilled in the art to refer to a computer or programmable circuit having a memory, inputs and outputs and a CPU, or equivalent circuit. In this manner the power unit may be used to more finely tune the motion of the gate to achieve a smoother cycle, avoid mechanical stresses to the gate, or otherwise program the action of or access to the gate. Use of the microprocessor allows the power supplied to the gate to be programmably varied during the cycle according to a calculated acceleration profile. Such a method and apparatus for moving a gate according to a calculated or predetermined acceleration profile is disclosed in co-pending application entitled DYNAMIC ADJUSTMENT METHOD and APPARATUS FOR CONTROLLING GATE OPERATION, by the same inventors and incorporated by reference herein.
It would be desirable to have a gate that completes an opening or closing cycle each time in a predictable, set period of time. This is most evident when multiple gates are used in tandem such as a master/slave configuration.
A problem, however, arises when the gate is of a different inertia or effective mass than that of one calculated by or assumed in the programming of the microprocessor, which might be based on a gate of standard inertia or mass. This may be caused by many environmental variables, such as wind blowing with or against the opening gate, a child stepping on the gate for a ride, when dirt or ice is caught in the mechanism of the gate, etc. It can also occur when the gate itself has been improperly mounted or has become misaligned over time. The microprocessor, programmed to execute an acceleration profile for a gate of a given mass, will take longer to complete a cycle when the gate has a heavier effective mass than anticipated. Likewise, the gate will complete the cycle more rapidly when the gate has a lighter effective mass than anticipated, for example when it is being pushed by wind or out of plumb or on a downward slope.
Moreover, in some applications a microprocessor-controlled powered gate may be moved according to an acceleration profile having different phases, the phases calculated to achieve a smooth action of the gate through the cycle. For example, a gate may be run through acceleration, running and deceleration phases, which allow the gate to be efficiently moved and come to a smooth stop. From this initial measurement of sampling an appropriate acceleration profile is determined to bring the gate from an initial position, through acceleration, running and deceleration phases. This phased cycling method is also predicated on an assumed mass for a gate and it is desirable to cause the gate to complete the cycle of phases each time in the same period of time.
A solution to the above problem has been devised. With a desired time to complete a cycle known, the effective inertia or mass of the gate is first measured upon initial movement of the gate. The output of the power unit can then be controlled by an acceleration profile varied to move the gate through the cycle in the desired time. This initial test of the effective inertia or mass of the gate can be taken with each initiation of a cycle so that, for example, a gate stopped in mid-cycle will reinitiate with the test when it is again moved, perhaps in an opposite direction.
Where the power unit is an electric motor, a measurement of the current needed to power the motor correlates with the effective inertia or mass of the gate. The desired cycle time, known output of the motor and the effective inertia or mass can then be factored to calculate an acceleration profile to be executed to cause the gate to complete its cycle within the desired time period.
This same method may be used with a phased cycle type of acceleration profile. The phased acceleration profile may itself be calculated according to an initial measurement of the mass of the gate, then, further attenuated to cause the gate to complete all of the phases, the cycle, in the desired period of time.
For an electric motor, for example, the current needed by the motor to produce sufficient force to move a gate is proportional to the effective inertia or mass of the gate; a greater effective mass of the gate will require greater current to move the gate. The microprocessor can then dynamically program the acceleration, running and deceleration phases through the cycle, determined by calculation from an algorithm or from a lookup table, to achieve a completion of the cycle in the desired time.
A method for moving a powered gate through an opening or closing cycle in a predetermined period of time is disclosed that comprises the steps of providing a gate that is mechanically connected to be moved by a power unit, wherein power to the power unit is regulated by a microprocessor; providing power to the power unit and measuring the power required of the power unit to move the gate; the apparent mass of the gate is then determined based on the power drawn by the power unit. The gate is then accelerated and decelerated through an opening or closing cycle based on an acceleration profile. The acceleration profile is either calculated by the microprocessor algorithmically. or by reference to a lookup table stored in memory by which the microprocessor retrieves appropriate instructions as to how to move the gate through a cycle.
Preferably the microprocessor is used to determine an acceleration profile comprised of an acceleration phase, a running phase and a deceleration phase that will move a gate of a given mass through a cycle in a predetermined period of time. The power provided the power unit, based on the measurement of the apparent mass of the gate, is attenuated to move the gate from a start position through the acceleration profile and complete the cycle to stop the gate at a predetermined end position. In most cases the acceleration phase and the deceleration phase take a substantially equivalent period of time, but this is not required.
In the preferred embodiment the power unit is an electrical motor and current provided to the electrical motor is regulated by a microprocessor. Current is provided to the electrical motor and measured by the microprocessor to determine a correlated apparent mass of the gate, and, current to the electrical motor is attenuated by the microprocessor to move the gate through the acceleration profile.
The microprocessor may be use to determine the apparent mass of the gate by providing a predetermined speed parameter based on a known mass of a gate. Electricity is supplied to the motor, and the current drawn by the motor is sampled a plurality of times to determine the load on the motor. The samples are then quantized and the used to arrive at an acceleration variable based on the samples. The speed of the motor is adjusted based on the acceleration variable, typically from the start position to a predetermined end position through acceleration, running and deceleration phases.
The present invention also encompasses an apparatus for moving a powered gate through an opening or closing cycle in a predetermined period of time. A gate that is mechanically connected to be moved by a power unit and power to the power unit is regulated by a microprocessor. The power required to cause the power unit to move the gate is first measured to determine a value proportional to the apparent mass of the gate, then the microprocessor determines an acceleration profile based on the determined apparent mass of the gate. The microprocessor then regulates the power to the power unit so that the gate is moved from a start position through the acceleration profile to stop the gate at a predetermined end position. This apparatus is further designed to be operated according to the above methods of this invention.